<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml"  
      xmlns:th="http://www.thymeleaf.org"
      xmlns:sec="http://www.thymeleaf.org/thymeleaf-extras-springsecurity4">
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
    <form th:action="@{/login}" method="post">
        用户名:<input type="text" name="username"><br>
        密码:<input type="password" name="password"><br>
        <input type="submit" value="提交">
    </form>
</body>
</html>